Kinetic Parameters for the Thermal Inactivation of Peroxidase and Lipoxygenase in Precooked Frozen Brassica Species

PÉREZ-CALDERÓN, JOHN; ZARITZKY, NOEMÍ; SANTOS, MARÍA VICTORIA; CALIFANO, ALICIA

JOURNAL OF FOOD SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 82 p. 1378 - 1386

0022-1147

Thermal inactivation of peroxidase (POD) and lipoxygenase (LOX), both enzymes present in broccoli and Brussels sprouts, is required before freezing, to obtain high-quality precooked frozen vegetables. Rate constants of a 1st-order biphasic model for the heat-labile and heat-resistant POD and LOX isoenzymes were determined at different temperatures (75, 80, and 90 °C) and the corresponding activation energies were estimated using nonlinear regressions. In the case of Brussels sprouts, the activation energies for the resistant and labile fractions were 56.3 and 62.5 kJ/mol for POD and 63.7 and 65.8 kJ/mol for LOX, respectively. For Brussels sprouts, different precooking times were tested to analyze the effect of residual enzyme activity on quality parameters and sensory attributes, after a frozen storage of 4 mo at -20 °C. A significant reactivation of enzyme activity after frozen storage was observed (especially in the case of POD) for short precooking times (